Emergency alert test review announced as some phones now 'unable to make calls' and millions don't receive alarm

A review will be carried out to find out why some mobile phones did not receive the test of a new national emergency alert system on Sunday.

Phones across the country rang out with a siren at 3pm as part of a government trial of the new national alert system, which will be used to contact residents in the case of a life-threatening emergency. It will be used in future to warn people about dangerous situations, such as floods or during terror attacks.

The test alert was set to be sent out nationwide on all mobile phones that are compatible with 4G and 5G. Phones let out a siren sound followed by the message.

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But although the 'vast majority of compatible phones' received the alert, according to The Cabinet Office, the 10-second alarm and message notification was not delivered to some mobile phones. Customers on the Three mobile phone network were among those to report not receiving the communication test.

The network provider said it would be working with the government to understand what had happened. A small number of people have also taken to social media to flag that they have not been able to make or receive calls since the 3pm alarm went off on their device.

The Cabinet Office stated that engineers had not spotted a trend of phone functions failing to work afterwards, but said officials were in the early stages of analysing the results of the trial run. A UK Government spokesman said: “We have effectively completed the test of the UK-wide Emergency Alerts system, the biggest public communications exercise of its kind ever done.

“We are working with mobile network operators to review the outcome and any lessons learned.”

In a statement, a